Railway cars are useful for transporting large amounts of cargo. Although in some applications it is desirable to manufacture large railway cars, the Association of American Railroads (AAR) has placed constraints on the size of railway cars for safety purposes. For example, the cross-sectional widths and heights of a railway car is limited by the AAR clearance limitations, which specify a maximum width and a maximum height of a railway car at the center of the railway car and also specify maximum heights and widths at other locations along the length of the railway car. Because of the AAR clearance limitations, designers often increase the cargo-carrying capacity of a railway car by increasing the length of the railway car. Unfortunately, as the length of a railway car increases, the width allowed by the AAR clearance limitations decrease to take into account the travel of a railway car around a curve. While traveling around a curve, a portion of a railway car may extend outside a clearance plane specified by AAR limitations, which is not acceptable. Therefore, stricter width clearance limitation is applied to longer railway cars to avoid a railway car making contact with a structure adjacent the railroad.
Thus, the AAR clearance limitations also generally limit the width-to-length ratio at which a railway car may be constructed and therefore further restrict the cargo-carrying capability of a railway car. The amount of cargo a railway car may carry directly impacts the profitability of a railway carrier and is therefore important. Thus, maximizing the amount of cargo a railway car can carry while staying within AAR clearance limitations is desirable.